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What Piece of Equipment on a Boat Is Most Important in Preventing Propeller Strike Injuries?

Written by Anthony Roberts / Fact checked by Jonathan Larson

what piece of equipment on a boat is most important in preventing propeller strike injuries

Boating accidents can be caused by various reasons and many of them involve the breakdown of different vessel components such as the propeller.

However, the majority of these damages may be prevented with a device. The knowledge about this safety equipment has been mentioned in guidebooks for those who study for the Boat Ed exam, and I am pretty sure most boaters have been through this test.

But if you cannot recall what the equipment is, refresh yourself with the answer in this post “What piece of equipment on a boat is most important in preventing propeller strike injuries?”

Furthermore, tips and notices while dealing with propeller strike incidents will be highlighted for boaters to stay safe. Continue reading to learn more!

Most Crucial Equipment in Avoiding Propeller Strikes & Other Safety Components on Boat


Propeller strikes can cause severe injuries. Thus, preparing safety gears to prevent these injuries is necessary.

Even if there are various equipment that may assist operators to assure the safety while dealing with propeller strikes, the ignition kill switch is the best option for boaters in this case.

The ignition switch, also known as the motor kill switch, is one of the most crucial pieces aboard a boat for reducing propeller injuries. This device is designed to shut down the boat engine abruptly and stop propeller rotation in order to avoid a propeller striking disaster. The easiest approach to avoid an accident is to ensure that no one is staying close to the propeller while starting the boat’s motor.

However, as I have mentioned above, there are other tools and devices that could help boat captains manage the situation. Here is a list of propeller safety gadgets that you may purchase for your vessels:

  • Ladder interlock: This connects the open water platform and ladder to the motor. It triggers a warning sound and turns off the motor. However, propeller mishaps are more likely to occur underwater than on the ladder.
  • Automatic censor: This device alerts when an individual is on the water’s surface and shuts the boat’s engine down.
  • Propeller guard: Because this equipment secures the propeller, the possibility of creating injuries is eliminated. However, it is not appropriate for bass vessels, ski boats, or high-speed watercraft.
  • Propeller cover: Even though this device is not designed to keep the motor running, it does maintain the propeller stability when it is not in exposure to water.

What Are Propeller Accidents and How to Prevent Them


1. The definition of propeller strikes

If a boat’s propeller collides with a passenger underwater, a propeller strike occurs. This frequently leads to significant damage, and in extreme cases, death.

Because it operates underwater, a vessel’s propeller is not visible to passengers, controllers, or swimmers. Hence, there is a threat of propeller impacts when it contacts an unseen object like heavy, thick moss or any swimmers and divers.

Propeller accidents are most common when there are people participating in water activities, such as water skiing and wakeboarding. Another typical reason is people diving off the stern of the vessel.

2. How to avoid propeller strike incidents?

While propeller accidents are hazardous, the majority of them can be prevented. To avoid a propeller collision, take the following precautions:

  • Verify that everyone has safely boarded before operating the vessel’s motor.
  • Do not get out of the water by climbing on the outboard engine.
  • Lower your boat’s velocity when you reach a busy area or anchorage. Always remember that swimmers or divers are heavily occupied in these populated areas.
  • Assign a scout to help you keep an eye out for anyone on the water’s surface.
  • Spend some time teaching people onboard about the position of the propeller and the risk it might cause.

What to Do When Encountering Propeller Injuries

In a split second, a conventional boat propeller has the ability to harm a person’s body. To start, you must understand why propeller strikes are so dangerous. A typical three-blade propeller rotating at 3,200 rpm can take up to 160 hits per second.

If propeller strikes occur, the reason for the occurrence should be recorded in an engine guidebook. In the case of an emergency and a blade tip failure, the entire engine needed to be dismantled. Before properly checking the rotors, turn the motor off.

Aside from being aware of this situation as well as having a professional operator onboard, I would suggest having a solid propeller cage. I’ve haven’t seen one attached to an outboard motor, but they’re easy to construct and install on standard shafted propellers. Some rudders may need the use of a cage, while others are cages themselves, creating a ducted effect.

To learn more about devices that help preventing propeller strike collisions, check out this video here:


To minimize catastrophes caused by propeller hits, the operator must also use the ignition kill switch lanyard. It is connected to the safety switch and fastened around the operator’s wrist. Therefore, having an ignition kill switch is mandatory for every boat owner in the US. Please install this device on your vessel as soon as possible.

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